I just had someone pm me that said the book arrived yesterday and i need to mark them recieved so she can get her credits. I didn't go to my mailbox, we've been in negative numbers, the box is frozen and I need to buy that lock stuff that defrosts the key locks. I marked the books received even if I don't know if there in the box or not.

My question is...what is your wait time before you send emails? 1 day seems like to quick to send an email.

I wait between 1-2 weeks...just in case someone is away or something.

I mostly wait a week before asking and only to have them let me know if they didn't get it so I can contact the PO. It's probably a member who is getting frustrated that so many people don't mark received without prompting. Personally, I'd reply nicely to let them know what the situation is, maybe even apologize for the delay. But I wouldn't mark it until I saw it. You're well within the timeframe according to guidelines.  What if they sent you a damaged book or some other unanticipated problem?

I usually wait 7-10 days before I message someone.  You never know if someone in away for vacation or business.  Though I do seem to have been doing a lot more often in the last year or so.  

Like the above I usually wait a week or so and also seem to be having to do it more often lately. 

I'm impatient, I send them a note after 5 days politely including PO info of delivery date and time.

I thought under 24 hours was a little quick but I did mark it received even though I don't have the book yet. 

I like the 5-7 days that all of you do. 

24 hours doesn't seem appropriate in the sense that somebody could be sick and doesn't go to the mailbox right away or in my case, we had negative temperatures and snow that have kind of locked some of our things like the big mailbox we all share. I'm also thinking there are people who go away for the weekend, and so if something arrives on a Saturday, they may not get to that until Monday.

Plus there are times something registers as delivered and it's delivered the next day.

I PM after 3 or 4 days. My message includes something like, "Wanted to let you know that  this was scanned delivered. Please let me know if it didn't arrive." My logic is that if it was misdelivered, or is sitting behind a potted plant on the porch, it's better to start the search right away.

Oh that makes sense Patty!

Actually, I usually mark it received the evening I get it. But then I'm retired.  However, I never email someone about acknowledging a book I sent them until a week after they receive it---all my books have tracking. Sometimes I have to send a second e-mail a week later too. Usually, they respond to that, unless they've been kidnapped by aliens.

Like Thomas, all my books are sent with tracking. So when I expect it has been received but not acknowledged, I check USPS first to verify the PO says it was delivered. I usually wait 3-4 days after PO says 'delivered' before I PM , including the tracking number at that time. When it passes over a week without being marked ' received' and I have not had a PM from the recipient explaining life got in the way  ( hospitalization, family emergency, travel delay, etc), I will message TPTB for intervention. 

I also give it between 5-7 days before sending a PM about it.  I've had stuff "out for delivery" for 3 days before I actually get it.